Try it with RLS policies that have any plain JOINs in them to reference other tables and you'll see execution times balloon massively (as in, orders of magnitude worse) for a lot of simple use cases, because it's then doing the RLS checks against every involved table to determine if your original RLS check is allowed to use them. The only way around that if you have multiple tables involved in determining access is to use cached subqueries with SECURITY DEFINER functions that aren't subject to the recursive RLS checking.